Just to clarify are you talking about them mpreging you? or you mpreging them? The reason i ask is cuz from what i have explored of the game if you have the mpreg ability then anyone who has a penis can technically impregnate you. If you are having trouble getting that to happen then you may want to invest in the fertility+ feat you can either get it from Doctor Matt via his volunteer feat menu or you can get it from Doctor Medea by completing a little errand for her then going into her pregnancy menu. I hope that helps.